U.S. inspectors say a $200 million American program to improve the literacy of Afghan soldiers appears to be falling short of its goal.

The NATO-led coalition set a goal of having 100 percent of Afghan security forces able to read and write at a basic level by the end of 2014.

The Office of the Special Inspector General for Afghanistan Reconstruction, which was created by the U.S. Congress to account for spending in the South Asian country, said in a report that more than one-third of Afghan security forces were illiterate as of February 2013.

It said reaching 100 percent literacy might be "unrealistic."

It added that there is no way to independently determine how many soldiers have actually become literate.